Radiant heater



Dec. 27, 1949 w. E. cRANsToN, JR

RADIANT HEATER 2 Sheets-Sheet 1 Filed Jan. 20, 1947 gcccc:CGCQMWQQCccccccccc:ccccccccccacca: v7 n l O INVENTOR. W/LL/ M E., C Nsro/v JA.

M. W L A 4 TTORNEYS.

Dec. 27, 1949 w. E. cRANsToN, JR

RADIANT HEATER Filed Jan. 20, 1947 A INVENTOR E CRAN: jraw IIR.

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Patented Dec. 27, 1949 RADIANT HEATER William E. Cranston, Jr., Los Angeles, Calif., as-' signor to Thermador Electrical Manufacturing Company, Los Angeles, Calif., a corporation of California Application January 20, 1947, Serial No. 723,193A

2 Claims.

My invention relates in its broadest aspect to a radiant type wall heater having an electrical ,resistance unit as its source of heat and adapted to be installed flush with the surface of a wall. More specifically my invention relates, and has to do with, the details of construction which permit locating a control switch adjacent the top of the heater, but in thermal isolation from the rest .of the heater.`

Radiant type wall heaters of the general type hereindescribed have been generally known and widely used in the construction industry. I-Iowever, heretofore it has always been necessary to .put the control switch at the bottom of the heater. Such a location was highly inconvenient in `that it required stooping to operate the switch. .This location Was made necessary because of the fact that heretofore known construction would allow the switch if pl-aced at the top of the heater to become overheated by the heat conducted and convected from the resistance unit, .thereby resulting in early failure of the switch due to thermal decomposition.

As is well known, most modern building codes do not permit installation of electrical equipment without the approval of the Underwriters testing laboratory. As radiant type heaters of this classification have heretofore been constructed, the Underwriters testing laboratory would not .approve the location of a switch in the top of the heater. It is an object of my invention to produce an velectrical radiating heater of the full length type wherein the switch may be placed at the top of 'the heater for ease and convenience of operation. Itis a further object of my invention to so construct this type of heater that even though vthe switch is placed at the top of the heater it is, for all practical purposes, thermally isolated .from the source of heat; therefore, not subject to thermal failures. Heaters of the type herein described containing the details of the constructions to be hereinafter explained, have been approved by the Underwriters laboratory for general use.

With these and other objects in view, the invention consists in the construction, arrangement and combination of the various parts of the device whereby the objects contemplated are attained, as hereinafter set forth, pointed out in the appended claims, and illustrated in the ac'- companying drawings.

In the drawings:

Figure 1 is a front elevation of a heater embodying the principles of my invention.

Figure 2 is a back elevation of the heater shown in Figure 1.

Figure 3 is a side elevation, partially in section, of the heater shown in Figure 1..

Figure 4 is a sectional view taken on line 4-4 of Figure 2.

Figure 5 is a view taken on line 5-5 of Figure 2.

Figure 6 is an enlarged sectional view taken on line 6-6 of Figure 1.

Figure '7 is -a fragmentary sectional view taken on line l-l of Figure 6.

Figure 8 is a partial sectional view taken on line 8-8 of Figure 6.

Figure 9 is a fragmentary sectional view taken on line 9--9 of Figure 8.

Figure l0 is a fragmentary section of a mounting post used to mount the resistance unit.

Referring more specifically to Figures l-3 inclusive, my invention includes generally a can or electrical outlet box II) adapted to'be installed within the partition of -a wall, a heat reflector I I, an electrical resistance unit I2, switching means I3 connected in electrical series with the electrical resistance unit I2, and a cover or guard I4.

The outlet box I0 is of standard construction vand comprises a substantially rectangular allmetal box having an opening I5 in the top or any other convenient location adapted to receive an electrical conduit or cable (not show n), and is formed with outwardly projecting flanges I6 (see Figure 6). The heat reflector II is substantially semi-cylindrical in shape and is formed of any material suitable to withstand the heat generated by the electrical resistance unit I2 and which will act as a heat reilector. The reflector II is closed on both ends by a cap I1 which is substantially semi-circular in shape and is formed with an upturned mounting flange I8 (see Figures 6 and 8). The cap I1 is secured to the reflector II by means of sheet metal screws I9 (see Figure 2) and by a return lip 20 extending the full length of each side of the reflector II. The end plate I1 is also formed with substantially radially extending projections 2l which abut against the electrical outlet box IIJ and act as spacers for the proper installation of the heater. The flange I8 extends around the periphery of the spacing extensions 2| thereby adding strength to the spacers. The return lip 20 is formed with a plurality of slots 22, the purpose of which will be explained later.

The cover plate Il is substantially rectangular in shape and is formed with two principal sections, that is, a grilled or louvred section comprising a plurality of transverse bars spaced to dene a plurality of radiant heat passing openings 3I and a switch mounting section. The heat passing section is secured to a mounting iiange 32 by a plurality of substantially narrow connecting sections or webs 33 which dene a plurality of openings. 34. The transverse vbars 30 .are arcuate in shape and are formed `with an extruded or upturned edge 35. The arcuate shape and the upturned edge add strength to the structure and permit the manufacture of the cover plate I4 of a relatively light gauge material. The web -33 and holes 34 are also formed with an extruded or upturned edge 36 which permit the use of` .a

relatively light gauge materialv andalso-.narrower sections in the web 33. The mounting ilange 32 is formed with a plurality oi apertures3'l adapted to receive mounting screws 38;

Spaced on the upturned edges to corre-.H

spond with the spacing oi the slots 22 in the return lip 20 are a plurality olf ears 39 which are adapted to be inserted through the slots 22 and then crimped over to hold the-.reilector II securely in position on the guard I4.

The switch mounting section of the cover plate I4 is located at the top of the cover plate I4 and isprovided with a baffle 4U having substantially the same shape asV the inside dimensions of the outlet box IU and is adapted to isolate the switch I3 from any convection currentsarising from the surface of .the reflector II. The baille is spaced above the end plate` I 'lso that one of the plurality of openings 3| is located between the Ybaffle 40 and the end plate I l, thus-permitting the escape of any Convection current. The switch mounting section is connected ,to the heat passing section by relatively narrow webs 4I. The webs 4I are bounded byan extruded lip 42 which also permits the use ofa relatively light gauge materialA anda much narrower section. The switch mounting section is also formed with an opening 43, the purpose of which will be understood later.

The baille 4U isl substantially L-shapedhavng a projecting heel 44 adapted .to act as a spacer Vfor the switch mounting foot 445 in a position remote from the cover plate I4. The baille 40 is secured to the .cover plate vI4 by spot welding the spacing `heel 44 to the cover plate .I4 or by any other suitablemeans.

Referring .to Figure 10.1 have illustrated the method preferred by rnev for-.securing the resist- .ance unitV I2 in place with respect to the reflector 'Iii is formed in theshape of ka cottenpin havingy a ,Y `loop fil on one end thereof adaptedto t .over and hold the wire oftheresistance coill I2. The binding wire lfis insertedv through the longitudinal bore 'l2 andthe endsfldand 1,9 bend .outwardly to prevent the .wireiromialling out of the bore 1.2..

The switch I3 may-be cfa-ny suitablacommercially available electrical switch having sufficient current carrying `capacity .to .withstand .the .load

of e the resistance. unit I2. andfshould v.be,.1;1rc' vide9:l

4 with terminals and 6I and an operating handle 62. The switch I3 is mounted by means of screws 63 on the spacing foot 45 and is spaced with heat insulating washers 64 so that the end of the operating handle 62 is ush with the outside surface of the mounting plate I4, thereby preventingl the accidental operation of the switch byanyone who happens to be passing.

It will be noted that due to the construction 1 herein described, the switch I3 is in substantial thermal isolation from the heat source of the -heater which permits the installation of the switch I3 in such a desirable position as the top ofthe cover plate I4. As will be readily understood ,iny the-operation of the heater, the bars 30 will absorb some of the radiant heat from the heating element I2. However, due to the relatively narrow section of the webs 33 and 4I, a relatively smallY amount of heat is conducted to either the mounting ange 32 or the switch mounting section of kthe cover I 4 so that the area surrounding the vswitch Aoperating handle '62 will not'become overheated and will not interfere with the operation of theswitch .'I3. The switch I3 is further .thermally conductively isolated from the grills 3D `'ar1d.from. any' heat radiated by the resistance unit I2 in that the only heat which can reach the switch I3 by means of conduction must pass through the screws 63. When Vit visunderstood that vrelatively little heat is conducted into the .switch mounting section of the cover plate I4, it will be seen that the amount of heat conducted through the screws 63 to the switch I3 is negligible.

It .will further be seen that the switch I3 is l`thermally'convectively isolated from the source otheat or any yheat generated b y the resistance `unit I2 which may be absorbed by the back of -thereilector i I and conducted upwardly by convection `currents .because of the baille 'I0 and the opening SIA located between the end plate I1 and the baffle 4U.

vOne of the principal advantages of a heater constructed according' to the proportions and dey Vtailsdisclosed in the drawings is that the heater can be provided tall enough to supply radiant heat` vtosubstantially the entire body length of the user without making it unduly wide. The general commercial practice in manufacturing this type .of heater has been to make `the heater approximately four feet high and position the basrevthereof substantially at the `iioor level, vthereby placing the switch 52 four feetfrom the floor.

In View of, `the `fact that this type heater is usually intended for installation in bathrooms, and` in view of the further fact .that Vmost modern'` apartments and -small. bungalows ,contain batllilrocmswhich tend to be crowded, the heater lliselosed herein `is ideal in that it can be placed inconned areas and still effectively heat the vbody ofrthose desiring touserit.

It will thus bessen that ,I have accomplished theobjects.originally. sought, that is, the, production of a radiant-type heater which can be placed in conined areas, which would otherwise ,present a r diiiiculty in'stoopingto Vthe bottom to turn theheater ofi. and stillrender ,the V-control means readily accessible.l A furtheradvantage .liesin the .fact that in viewof the height. of the invention in what I have conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of my invention, which is not to be limited to the details disclosed herein, but is to be accorded the full Scope of the claims so as to embrace any and all equivalent devices.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

l. A flush-type electric wall space heater comprising: a substantially impervious sheet metal box adapted for vertical installation in a wall recess, and when in such position including a back, top, bottom and sides and being open at the front, an impervious concave reflector comprising a vertical concave reflector member and substantially flat top and bottom closures and being open at the front, said reflector being mounted in said box to define a passage between the lower end of the reflector and the bottom of the box, a vertical passage between the back and sides of the reflector and the back of the box, and a passage between the top of the reflector and the top of the box, said passages being intercommunicating, an impervious substantially horizontal partition across said box near its upper end, the last said passage being defined by the upper face of the reflector top and the lower surface of said partition, open communication from the front of the reflector and box assembly at the bottom thereof leading into the first of said passages and at the top thereof leading from the last of said passages, whereby convection currents may enter below said reflector and travel upwardly between said reflector and said box and be exhausted at the upper forward region of said box and reflector, an electric switch chamber being formed at the upper end of said box by said horizontal partition in the upper terminal parts of said box, an electric resistance heating element mounted in said reflector, electric wiring for said heating element coupled with said switch, and a protective flush-type grill adapted to be mounted upon the wall adjacent the boundaries of the wall recess and in direct association with said box and reflector assembly, said grill being formed with openings near the top and bottom communicating with the said top and bottom horizontal passages which are adapted to `convey convection currents.

2. A flush-type electric wall space heater having a length substantially greater than its width comprising: a substantially impervious sheet metal box adapted for vertical installation in a wall recess and when in such position, including a back, top, bottom and sides and being open at the front, an impervious reflector assembly comprising a vertical concave reector member and substantially flat top and bottom closures and being open at the front, said reflector assembly being mounted in said box to define a passage between the lower end of the reflector and the bottom of the box, a vertical passage between the back and sides of the reflector and the back of the box, and a passage between the top of the reflector and the top of the box, said passages being intercommunicating, an impervious substantially horizontal partition across said box near its upper end, the last said passage being dened by the upper face of the reector top and the lower surface of said partition, open communication from the front of the reector and box assembly at the bottom thereof leading into the first of said passages and at the top thereof, leading from the last of said passages, whereby convection currents may enter below said reflector and travel upwardly between said reflector and said box and be exhausted at the upper forward region of said box and reflector, an electric switch chamber being formed at the upper end of said box by said horizontal partition in the upper terminal parts of said box, an electric resistance heating element mounted in said reflector, electric wiring for said heating element coupled with said switch, and a protective flush-type grill adapted to be mounted upon the wall adjacent the boundaries of the wall recess and in direct association with said box and reflector assembly, said grill being formed with openings near the top and bottom communicating with the said top and bottom horizontal passages which are adapted to convey convection currents, said grill being formed with guard members in front of said electric heating element, the major portion of the metal being removed in parallel lines adjacent to the side edges of said guard members, thereby reducing thermal conductive capacity between the guard members and the side and top anges of the said grill.

WILLIAM E. CRANSTON, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,484,170 Cannon Feb. 19, 1924 1,491,885 Robinson Apr. 29, 1924 1,948,402 Teller et al. Feb. 20, 1934 FOREIGN PATENTS Number Country Date 429,323 Great Britain May 28, 1935 522,821 Great Britain June 27, 1940 

